Blue-Green Algae

54 Pages·2012·1.59 MB·English

by  The Scottish Government

COVER
JOB No. 216138 2 DATE 02/04/12
(if applicable)
COLOURS CMYK TEXT 52 OPERATOR CW
SCOTLAND
ACCOUNT
PROOF No. P5 SIZE A4 NM
MANAGER
Cyanobacteria (Blue-Green Algae) in Inland
and Inshore Waters: Assessment
and Minimisation of Risks to Public Health
Revised Guidance 2012
Compiled by the Scottish Government Health and Social Care Directorates
Blue-Green Algae Working Group
Scottish Government Health and Social Care Directorates 2012
Cyanobacteria (Blue-Green Algae) in Inland
and Inshore Waters: Assessment
and Minimisation of Risks to Public Health
Revised Guidance 2012
The Scottish Government, Edinburgh 2012
© Crown copyright 2012
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This document is available from our website at www.scotland.gov.uk.
ISBN: 978-1-78045-677-5 (web only)
The Scottish Government
St Andrew’s House
Edinburgh
EH1 3DG
Produced for the Scottish Government by APS Group Scotland
DPPAS12623 (02/12)
Published by the Scottish Government, February 2012
CONTENTS PAGE NO

Foreword 1

Preface 2

Glossary of abbreviations 3

1 Introduction 4

2 Occurrence and appearance of cyanobacteria (blue-green algae) 5

3 Public health concerns 6

4 Local action plans 9

5 Assessing the nature and intensity of cyanobacterial blooms 10
- General provisions
- Defining an assessment programme
- Visual inspections
- Sampling and analyses

6 Assessments of the risks to human and animal health 13
- Responsibilities for risk assessments
- Types of risk assessment
- Content of risk assessments for individual waters
- Defining categories for frequency of occurrence or risks for cyanobacterial blooms
- Templates for risk assessments
- Specific considerations for public drinking water supplies

7 Risk Management and Risk Communication 16
- General requirements
- Triggers for action
- Specific actions in response to a cyanobacterial bloom
- Action to reduce the development of cyanobacterial blooms

8 Communications Strategy 23

9 Cyanobacterial Incident Investigation 24

References 25

Annex A Membership of Working Group 27
Annex B Cyanotoxins 28
Annex C Sources of specialist advice 29
Annex D Suggested framework for a Local Action Plan (LAP) 31
Annex E Recognition and identification of cyanobacterial blooms,
scums and mats and methods for sampling 32
Annex F Suggested templates for risk assessments 35
Annex G Extract on exposure guidelines from the WHO Document 37
Annex H Suggested text for warning notices 42
Annex I Media briefing notes 43
Annex J Regulatory Enforcement – Roles And Responsibilities 45
FOREWORD BY SIR HARRY BURNS, CHIEF MEDICAL OFFICER FOR SCOTLAND

In the autumn of 1854, an outbreak of cholera claimed the lives of some 600 residents of
the Soho area of London. In studying the distribution of these cases in the areas affected, a
local doctor, Dr John Snow, developed a view that the source of the outbreak was the water
pump in Broad Street. It is said that, at a subsequent meeting, Dr Snow managed to
convince a sceptical board of guardians for the parish of St James that there was sufficient
evidence to warrant an appropriate intervention – the removal of the Broad Street pump
handle. The handle was removed and the outbreak ended.

The story of Dr John Snow and the Broad Street pump handle holds a prominent place in
the history of public health in the UK. Not only did it establish contaminated drinking water
as the source of a major killer, it is also credited with marking the birth of modern
epidemiology. Now, some 150 years on, protection of the public health relies less on the
inspired efforts of individuals but rather on what we often describe as ―the organised efforts
of society‖.

However, ensuring the availability of reliable sources of clean water remains a cornerstone
of these efforts.

The original development of this document in 2002 and the subsequent implementation of
its guidance have provided an excellent example of successful channelling of the organised
efforts of the public health and the environmental agencies in Scotland. This joint working
has continued in the development of this 2012 revision which now includes the provisions
necessary to address the relevant responsibilities of the Scottish Government under the
European Union revised Bathing Water Directive.

I am grateful, therefore, to the members of the Blue-Green Algae Working Group who have
contributed to the revision of this document, and I thank them for the opportunity to provide
this introduction.

Sir Harry Burns
Chief Medical Officer for Scotland
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PREFACE

This is the second revision of the guidance document under the same title that was
published initially by the Scottish Executive Health Department in 2002, and revised for the
first time in 2007.

The approach advocated for managing the risks to human and animal health of exposure to
cyanotoxins continues to centre on production and implementation of ―Local Action Plans‖.
These should be co-ordinated by the NHS Boards in Scotland and should be agreed by the
various stakeholders identified herein.

This document includes guidance on the content and structure of these Local Action Plans
and should be regarded as a resource to assist in their production, as well as fulfilling the
requirements of Article 8 (cyanobacterial risks) of the Bathing Water Directive (2006/7/EC).

The Scottish Government Health and Social Care Directorates (SGHSCD) propose to
review and, if necessary, reissue this guidance document every five years. However, it is
recognized that the value of this guidance lies in its practical implementation. The SGHSCD
would therefore welcome feedback, which should be addressed to the SGHSCD‘s Scientific
Adviser at St Andrew‗s House, Edinburgh EH1 3DG. Should this feedback indicate a
specific need, then a further version of this guidance will be produced sooner.

The impact on human health associated with cyanobacterial contamination of recreational
and drinking waters in Scotland remains, thankfully, low based on evidence of incident
reports. The potential risks to health, however, remain real. Climate change predictions
suggest that over a longer term, changes in temperatures and weather patterns may
increase the scale of hazard presented by cyanobacterial blooms. This in turn may
increase the scale of risk to human health. Planning and preparedness with respect to
cyanobacterial contamination will therefore remain important for the foreseeable future.

Dr Colin Ramsay
Chairman of the Blue-Green Algae Working Group

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GLOSSARY OF ABBREVIATIONS

CPHM Consultant in Public Health Medicine
COSHH Control of Substances Hazardous to Health
DWQR Drinking Water Quality Regulator
EHO Environmental Health Officers
FSA Food Standards Agency
HSE Health and Safety Executive
HPS Health Protection Scotland
LPSs Lipopolysaccharides
LAP Local Action Plan
LAs Local Authorities
LAEH Local Authority Environmental Health
MHSWR Management of Health and Safety at Work
NPIS National Poisons Information Service
SAC Scottish Agricultural College
SACVSD Scottish Agricultural College Veterinary Science Division
SEISS Scottish Environmental Incident Surveillance System
SEMD Security and Emergency Measures Direction
SEPA Scottish Environment Protection Agency
SGEED Scottish Government Enterprise and Environment Directorates
SGHSCD Scottish Government Health and Social Care Directorates
SNARLs Suggested No Adverse Response Levels
WHO World Health Organization

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1. INTRODUCTION

1.1 This document, prepared by a Working Group established by the Scottish
Government Health and Social Care Directorates, provides guidance to Directors of Public
Health, to Heads of Environmental Health in Local Authorities (LAs), and to others in
Scotland, on possible risks to public health of cyanobacteria (blue-green algae) in inland
and inshore waters. It updates previous guidance under the same title that was published
by the Scottish Government Health Directorate previously in 2002, and revised in 2007.

1.2 The remit of the Working Group was:

i. to review previous guidance in the context of advances in scientific knowledge and,
in particular, to consider the implications for the public of exposure during recreation
and work and of exposure from food and water;
ii. to review previous guidance on monitoring and risk assessment in the context of
recent experience in Scotland and elsewhere; and
iii. to provide further guidance.

1.3 The membership of the Working Group is given in Annex A.

1.4 The guidance takes account of relevant peer reviewed literature, expert group
guidance from international bodies (e.g. WHO) and the expert opinions of the Working
Group members. It takes account of current World Health Organisation (WHO) guidance
summarised in ―Toxic cyanobacteria in water. A guide to their public health consequences,
monitoring and management‖ (eds I Chorus and J Bartram) published in 1999 by E&FN
Spon, London, on behalf of the WHO. The guidance given in this report also provides for
Scottish compliance with the requirements of Article 8 of the revised Bathing Water
Directive (2006/7/EC)
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2006:064:0037:0051:EN:PDF
A formal systematic review as such was not conducted however, Working Group members
updated relevant sections of the report based on their knowledge of relevant literature and
issues.

1.5 This document will be updated every five years. It is accepted, therefore, that while
certain details (such as contact details in Annex C) are correct at the time of issue, they are
subject to obsolescence during this period.

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2. OCCURRENCE AND APPEARANCE OF CYANOBACTERIA (BLUE-GREEN ALGAE)

2.1 Cyanobacteria occur in fresh, brackish and sea-waters throughout the world. In
Scotland, they can occur in quantity in lochs, ponds, canals, rivers, reservoirs and coastal
waters. While usually green or blue-green in colour (hence the term blue-green algae), they
may be khaki, blue, black, dark brown or red (hence the preferred terminology now used is
cyanobacteria).

2.2 When present in high concentrations, colonies of cyanobacteria can often be seen
with the naked eye: they may resemble fine grass cuttings or take the form of small irregular
clumps or pinhead-sized spheres. Cyanobacteria in high concentrations in the water column
can form ‗blooms‘ and, when blown on to a downwind shore, form scums which can be up
to a few centimetres thick. Scums may also be seen in slow-flowing rivers and streams
downstream from lochs. Decaying scums, due to other naturally-occurring microbes or
bright sunlight for example, can appear bleached as sky-blue, grey, or white masses.

2.3 Cyanobacteria may also grow on the bottom of shallow water bodies and on
shoreline rocks and sediments. They occasionally form thick gelatinous mats, which may be
exposed as the water level falls or may detach from the bottom and reach the shoreline.
These mats are usually very dark in colour (black, dark brown or green), are cohesive and
are sometimes mistaken for sewage.

2.4 Growths of some varieties of water plants (particularly duckweed) that float on the
water surfaces can be mistaken for surface scums of cyanobacteria.

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3. PUBLIC HEALTH CONCERNS

3.1 Surveys in different parts of the world have found that between about 45% and 90%
of blooms of cyanobacteria produce toxins (cyanotoxins). These toxins are largely retained
within the cyanobacterial cells during their development and growth phases and are
released, in the main, on cell death (Codd GA & Bell SG (1996)).

3.2 The range of cyanotoxins is diverse and includes neuro- and hepatotoxins, skin
irritants, and inflammatory agents. A cyanobacterial bloom may contain more than one
species, each producing the same or different toxins, either singly or in combination. In
addition, the toxicity of one species might change over time dependent on the nutritional
state of the algae, and for different places on a particular water body. Further information on
cyanotoxins and their health effects is given in Annex B.

3.3 Evidence on toxicity is drawn from reports of the effects of exposure of people and of
animals to cyanobacterial blooms and from laboratory investigations of cyanotoxins.
Overall there have been relatively few published reports worldwide of significant human
health impacts associated directly with exposure to cyanotoxins linked to cyanobacterial
incidents. However, surveillance of illness associated with such exposures is likely to be
incomplete.

3.4 In 1989, a group of soldiers took part in kayak training, including rolling and
swimming exercises, at Rudyard Lake in Staffordshire. Two became severely ill with
atypical pneumonia; others reported abdominal pains, vomiting, diarrhoea, blistering of the
mouth and sore throats. Further incidents involving human health impacts have occurred
after recreational contact with cyanobacterial scums and blooms in UK inland waters in
recent years. The effects were probably associated with exposure to cyanobacteria and
ingestion of the toxin-containing cyanobacterial scum.

3.5 Gastroenteritis, neurological effects, acute hepatocellular damage and skin irritation
have been reported from other countries. Illnesses and deaths of haemodialysis patients,
attributed to exposure to cyanotoxins in inadequately-treated water, occurred in Brazil in
1996. Further exposures of haemodialysis patients to cyanotoxins, followed by illness,
occurred in Brazil in 2001.

3.6 Ingestion of hepatotoxic and neurotoxic scums of cyanobacteria is reported to have
caused the deaths of cattle, horses, sheep, dogs, and a wide range of wild terrestrial
animals and domestic and wild birds. There is also evidence that cyanotoxins have been
major contributors to fish kills and the deaths of other aquatic animals.

3.7 Another potential source of intoxication for both animals and humans is via
bioaccumulation of cyanotoxins in the food chain. The principal concern here would be
accumulation of the toxins in shellfish including freshwater and brackish-water mussels and
in fish. However, no cases of intoxication from such sources have been reported to date in
Scotland.

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